Method of decorating large surfaces by photography



Patented May 26, 1936 UNITED STATES PATENT OFFICE METHOD OF DECORATINGLARGE SURFACES BY PHOTOGRAPHY Eugene M0110 and Henry Charles Merrett,London, England 3 Claims.

This invention relates to a process for photographically decorating thesurfaces of structures, and particularly theatre walls, exhibitionstands, facades and the like. The principal object of the 5 invention isto enable decorations to be applied directly by photography to the saidsurfacesas distinct from former methods which comprised the photographicdecoration of panels, plaques and Wall coverings and the piece by pieceapplication of such panels, plaques or coverings to the surface of thestructure to be decorated. A process in accordance with this inventionenables the surface of a structure to be decorated much more quickly andeconomically than heretofore and affords a much greater scope for theattainment of artistic, bizarre and other effects appropriate from thearchitectural design or features present or for the general art schemeto be adopted. It further enables a decorative ensemble to be tested onthe site before the actual decoration is applied.

Finally, it enables one decorative scheme to be substituted by anotherin a minimum of time and at relatively small cost. To give one practicalexample, the invention enables a cinema theatre to be decorated orre-decorated in a single night.

According to this invention a process for deccrating structures of thekind in question comprises preparing the surfaces thereof by theapplication of a preliminary coating of a preparation such as plasticpaint which is neutral to photographic emulsion and is adapted forimparting a bite or tooth eifect suflicient for ensuring adherence ofsuch emulsion, spraying the prepared walls or surfaces with a fastlight-sensitive emulsion, projecting a decorative image on to thesensitized surface, and applying developing and fixing solution orsolutions to the exposed surface by means appropriate for the quickcovering of such surfaces with said solutions, whereby the photographicimage is uniformly developed and fixed over the whole of such surface.The resulting images may be toned by any of the toning processes knownto those versed in the art, as for example by the spraying or otherwidespread distribution of toning solution over the decorated surface.

The invention resides not merely in a general direction of the processof decoration but also in certain essential provisions for enabling theproct ess to be practiced in a useful and advantageous manner.Primarily, the nature of the surface to be decorated must be appropriatefor the treatment it is to receive. Thus, it must be made suit- 55 ablefor the adherence of the emulsion tube sprayed upon it. Also, it must bemade neutral to that emulsion so that it can have no deleterious effectupon the sensitivity of the emulsion. Consequently, it is necessary toprepare the surface by applying a first coating, or substratum, of a 5liquid substance which will produce a covering not inimical to theemulsion but capable of affording a bite or tooth effect sufficient toensure adhesion. The most advantageous preparation for this purpose is aplastic paint which is neutral 10 to the emulsion to be used and whichcontains a solid constituent, such as finely powdered or disintegratedasbestos, this constitutent being a medium appropriate for imparting theaforesaid bite or tooth effect. 15

Next in order comes the character of the sensitizing emulsion. It hasbeen suggested, for example, to sensitize the surfaces of fabrics andmaterials with gelatine, or gum, or albumen incorporating a bichromate.Any such method, how- 20 ever, is out of the question for the practicalcarrying out of the present invention on account of speedconsiderations, for in no case could an enlarged image thrown upon itgive a printable speed. The invention requires the employment 25 of areally fast emulsion in order that a practical exposure time may beadopted when using a projector for projecting images of such dimensionsand degrees of enlargement as are required for covering an entire wall,stage, or structure. 3 Thus, a speed of about 5 H. and D. is required inorder that a practical exposure time may be possible. Furthermore, thenature of the emulsion must be such as to be appropriate for quickWide-spread distribution by means of a spraying 35 device, and, finally,it must be of a sufiiciently stable and durable nature for enabling itto be transported without deterioration to the site where it is to beused. As an example, the first step in the preparation of an emulsion isto de- 40 termine, as by trial and error, a suitable viscosity for thespraying of the emulsion through an ordinary commercial spraying gun orsimilar spraying appliance. By adjusting the proportions of spirit,glycerine, chrome alum and other ingredi- 45 ents it is possible toachieve a suitable viscosity and to produce an emulsion which can besuccessfully sprayed. It is further necessary to test the emulsion underspraying conditions and to make microscopical examination of the testcoatings, in order to make such further adjustment of the ingredients asmay be necessary to satisfy the following requirements:- (a) theemulsion although churned up by the spraying gun and 55 mixed with airmust be of such a nature as to contain or occlude air bubbles of onlyvery small size, (12) the emulsion must be capable of homogeneous anduniform distribution and (0) its presence as a coating should bepractically invisible when the coated surface is viewed from a distanceof a foot or so away. The second step is to adopt a suitable balance ofsilver bromide, gelatine/silver ratio, excess of soluble bromide, and acertain quantity of free organic acid such as citric acid, so that theemulsion is capable of remaining in good condition for several weeks.This enables the emulsion to be taken in jelly form to a job at anydistance from its place of manufacture, and then to be re-melted to thenecessary temperative for spraying as and when required.

By carefully determining the exact amount of silver required to giveimages of the requisite density and having the free acid present, it ispossible, by using the correct exposure, to avoid over-development. Thatis to say, the image will develop right out to the desired density andwill not blacken further. This is of importance when the performance ofa decorating operation is carried out by ordinary workmen, for if theyshould be delayed a minute or two between the applications of thedeveloping and fixing solutions, the image will, nevertheless, notdevelop out too dark.

An example of an emulsion suitable for the practical carrying out of theinvention is as follows:

A solution of 1 kilogramme of silver nitrate is made in 7 litres ofdistilled water at 50 (3., containing 25 grammes of citric acid. This ispoured slowly into a crock containing 17 litres of distilled water, inwhich are dissolved 0.7 kilogramme of potassium bromide, 0.6 kilogrammeof gelatine and 30 grammes of potassium iodide at a similar temperature.The solution in the crock is stirred while the acid silver solution ispoured into it. 0.8 kilogramme more of gelatine is then stirred in, andthe emulsion kept at a Warm heat of 50 C. for one hour. It is then setin ice, and after 24 hours remelted, and 1.25 litres of ethyl alcohol, 8grammes of chrome alum previously dissolved in a litre of water, and0.25 litre of glycerine are added. Such an emulsion will keep for two orthree weeks, and can be repeatedly remelted.

According to the design of the artist or decorator, it may be desirableto use an emulsion giving soft, delicate gradation, or a very vigorous,to contrasting image. The emulsion given in the example has a gamma ofabout 3, and is a medium contrast emulsion for all-round work.Increasing the quantity of silver bromide or the proportion of potassiumiodide will render the emulsion more vigorous in the known manner.

The choice of gelatine may have to be varied to render the viscosity ofthe emulsion suitable for the particular nozzle of a spraying gun.Coignets or Nelsons No. 1, gelatine giving thinner or less viscousemulsions, while Heinrichs or Nelsons hard emulsion gelatine give moreviscous emulsions. The right proportion is best decided on by actualtrial. Equal parts of Coignets and Nelsons hard emulsion gelatine willgenerally give a suitable viscosity.

The finished image can be toned by spraying or hosing with suitablesolutions of well-known toning bath constituents. Also, a first image inone colour may be sprayed with acetate dope, whereupon a second coatingof emulsion may be sprayed, exposed and developed and, if desired, maybe fixed and toned to a second colour. By

this means, it is possible to produce twoor three-colour pictures ordecorative designs on the walls or decorative parts of a building or anystructure in situ.

For some purposes, a combined developing and fixing solution may besprayed. Thus, for example, a combined developing and fixing solutionmay be composed of metol grammes, hydroquinone 130 grammes, sodiumsulphite (crystals) 1 kilogramme, sodium carbonate (crystals) 1kilogrammes, potassium bromide 20 grammes, hypo 2 kilogrammes, and waterto make up 20 litres. Also, a combined developing, fixing and toningsolution may be sprayed. The final image may be washed with water sprayand a final coating of cellulose or other suitable lacquer may beapplied to preserve the surface decoration and to enable it to becleansed by washing when desired.

For the purpose of preventing damage or undue wetting of premises inwhich the decorations are carried out a system of guttering withsuitable sealing or packing may be applied along wall surfaces beneaththe areas to be decorated, so as to collect and run off the solutionsand wash waters employed in the process.

The surfaces treated may be of wood, such as the ply wood used forexhibition stands, shop display, cinematograph studio work, and so on.Or, when decorating buildings, the surfaces may be of cement, plaster,fibrous plaster, composition boards or slabs, and so on. The preliminarycoating of plastic paint enables any of these surfaces to take and holda coating of emulsion sprayed thereon and ensures that the emulsioncannot be deteriorated by any reactive matter contained in suchsurfaces.

Special decorative effects can be achieved by performing the process onsurfaces already architecturally decorated by modellings in bas relief.Part of the efiect is then attained by sculptured relief and part by thelight and shade of photography, which, combined with the bas relief, produces a very mystifying effect of depth. Such an effect could not beachieved by ordinary photographic processes requiring the rolling on ofemulsions or sensitive media. The improved process enables a completelyconstructed exhibition stand to be decorated exteriorly as well asinteriorly over its whole surface in a very short space of time. Thedecoration may, of course, include advertisement features relating tothe goods of the exhibitor and the surfaces treated may include those ofwalls, tower formations, roofs, canopies, show cases and other objectswhich could not possibly be decorated by ordinary photographicprocesses.

The light projection may be such as to illuminate the whole of thesurface to be decorated, as by employing flood lights with stencils,negatives or positives between the lights and the said surface. Or, aprojector capable of being directed progressively over the surface to bedecorated may be used and may receive stencils, photographic plates orfilms bearing appropriate designs to suit different areas of thesurface. As already stated, the emulsion has a suificiently fast indexfor enabling a light exposure by such means to be carried out in a timewhich is practical having regard to all the attendant conditions.

We claim:

1. Process for photographically decorating the surfaces of structures,and particularly theatre walls, exhibition facades and the like,comprismg covering said surfaces with a preparation which is neutral tophotographic emulsion and which is adapted. for imparting a, bite ortooth effect sufficient for ensuring adherence of such emulsion,spraying the covered surfaces with a fast light sensitive emulsion,producing an exposure of the sensitized surface by means of a lightprojector producing an image, and treating the exposed surface withdeveloping and fixing agents sprayed in solution form by quickly actingdistributive means.

2. Process for photographically decorating the surfaces of structures,and particularly theatre walls, exhibition facades, and the like,comprising coating said surfaces with plastic paint, incorporating asolid constituent for imparting a bite or tooth effect spraying on tothe coat of plastic paint a fast light sensitive emulsion, producing anexposure of the sensitized surface by means of a light projectorproducing an image, and spraying, developing and fixing agents insolution form on the exposed surface.

3. Process for photographically decorating the surfaces of structures,and particularly theatre walls, exhibition facades and the like,comprising preparing said surfaces with a plastic paint which is neutralto photographic emulsion and which contains a solid constituent adaptedfor imparting a bite or tooth effect sufficient for ensuring adherenceof such emulsion, spraying the prepared surfaces with a fast lightsensitive emulsion physically constituted so as to have a viscositysuitable for spraying, producing an exposure of the sensitized surfaceby means of a light projector producing an image, spraying developingand fixing agents in solution form on to the light exposed surface, andspraying a protective and washable coating over the photographicallydecorated surface.

EUGENE MOLLO. HENRY CHARLES MERRETT.

